It has been demonstrated, with several RNA viruses, that more than one RNA molecule is required for replication of the virus or expression of a virus related disease. The genome of cowpea mosaic virus (CPMV), a plant virus, is divided between two RNA components each of which are encapsulated separately. Both RNA components have polyadenylate sequences at their 3' termini. Employing methods that selectively bind RNA fragments that contain poly(A), we plan to determine the nucleotide sequences adjacent to the poly(A) termini of the two RNA components. The nature of the 5' termini of the RNA components is also under investigation. Attempts will be made to determine if the poly(A) segments are transcribed from poly(U) segments in the replicative form of CPMV RNA components. Using a rapid assay technique, we have found an electrophoretic mutant of the virus. This mutant was used to determine which RNA component carried the information specifying the smaller of the two capsid proteins. A similar investigation is underway to locate the gene specifying the larger capsid protein.